In UMTS (Universal Mobile Telecommunications System) networks, for the purpose of improving spectral efficiency and further improving data rates, by adopting HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access), it is performed exploiting maximum features of the system based on W-CDMA (Wideband Code Division Multiple Access). For the UMTS network, for the purpose of further increasing high-speed data rates, providing low delay and the like, Long Term Evolution (LTE) has been studied (Non-patent Document 1).
In the 3G system, a fixed band of 5 MHz is substantially used, and it is possible to achieve transmission rates of approximately maximum 2 Mbps in downlink. Meanwhile, in the LTE-scheme system, using variable bands ranging from 1.4 MHz to 20 MHz, it is possible to achieve transmission rates of maximum 300 Mbps in downlink and about 75 Mbps in uplink. Further, in the UMTS network, for the purpose of further increasing the wide-band and high speed, successor systems to LTE have been studied (for example, LTE Advanced (LTE-A)). For example, in LTE-A, it is scheduled to increase 20 MHz that is the maximum system band in LTE specifications to about 100 MHz.
As one of promising techniques to further improve system performance of Rel-8 LTE system, there is inter-cell orthogonalization. In LTE systems of Rel-10 or later (LTE-A system), intra-cell orthogonalization is achieved by orthogonal multiple access both in uplink and downlink. In other words, in downlink, mobile terminal apparatuses (User Equipments) are orthogonalized in the frequency domain. However, for inter-cell, interference randomizing by 1-cell frequency reuse is a base as in W-CDMA. The 3GPP (3rd Generation Partnership Project) has studied Coordinated Multi-Point transmission/reception (CoMP) as techniques for actualizing inter-cell orthogonalization. In CoMP transmission/reception, a plurality of cells coordinates to perform signal processing of transmission and reception on a single or a plurality of mobile terminal apparatuses (UEs). More specifically, in downlink, studied are Joint Transmission (JT), instantaneous cell selection (DCS) and the like (Joint Processing (JP)-CoMP).